1. Field of the Invention
The present invention relates to an apparatus and method of manufacturing absorbent bodies used in absorbent articles, such as a sanitary napkin, panty liner, incontinent pad, etc., for absorbing bodily fluids such as menstrual blood, vaginal discharge, etc., and absorbent bodies manufactured thereby.
2. Related Art
Conventionally, with the aim of enhancing handling-ability, etc., there is a demand for reduction in thickness of absorbent articles, such as a sanitary napkin, panty liner, incontinent pad, etc., for absorbing bodily fluids such as menstrual blood, vaginal discharge, etc. However, if the absorbent article is made thin, there arises a problem in that an absorbent body that is a component for absorbing and maintaining bodily fluids becomes stiff and solid, impairing flexibility.
Thus, an absorbent article is disclosed, for example, in JP-A 2003-038552 (referred to hereinafter as Patent Document 1).
The absorbent article includes a liquid permeable top sheet, a liquid impermeable back sheet, and an absorbent body interposed therebetween. The absorbent article has concave and convex portions arranged continuously on both faces to extend along the length direction of the absorbent body. With this, the absorbent body has a corrugated cross-section.
With this absorbent article, since the absorbent body is formed to have a corrugate section, the distance between corrugations can be adjusted in accordance with an applied force, leading to enhanced flexibility of the absorber.
With this absorbent article, however, since the absorber is formed to have a corrugated cross-section, the adhesion area is reduced between the absorbent body and the back sheet, degrading the linkage therebetween. As a consequence, even if the back sheet follows movement of clothing by a well-known displacement preventing means, etc., the absorbent body does not move together with the back sheet, and thus cannot follow movement of the clothes sufficiently. This may cause easy twisting of the absorbent body, resulting in possible occurrence of leakage of bodily fluids.
An absorbent article is disclosed, for example in JP-U 04-051930 (referred hereinafter as Patent Document 2).
This absorbent article includes a liquid permeable top sheet, a liquid impermeable back sheet, and an absorbent body interposed therebetween. A plurality of slits are formed in the absorbent body.
With the absorbent article, due to arrangement of a plurality of slits in the absorbent body, when clothing moves, the absorbent body moves and bends together therewith, so that the projection-side external surface of a bend opens the slits, whereas the inside of the bend closes the slits. With this, the absorbent body can deform, bend, etc., while restraining occurrence of a high-stiffness part at the bend, resulting in enhancement in flexibility of the absorbent article.
Moreover, as distinct from the absorbent article disclosed in Patent Document 1, a problem that the linkage between the absorbent body and the back sheet is degraded by a reduction in adhesion area therebetween, does not easily occur.
The absorbent body having a plurality of slits is manufactured by a method using the following manufacturing apparatus.
This manufacturing apparatus includes a conveying roller for conveying a continuous absorbent sheet, a slitting roller having on the external surface a plurality of slitting blades extending in a predetermined direction and arranged so that the slitting blades are pressed against the absorbent sheet conveyed by the conveying roller, a cutting roller for cutting the absorbent sheet against which the slitting blades are pressed and forming the absorbent body for absorbent articles, and a drive motor for rotating the rollers.
The manufacturing apparatus operates as follows. First, the conveying roller is rotated by the drive motor to convey the continuous absorbent sheet. The slitting roller rotated by the drive motor presses the slitting blades against the absorbent sheet conveyed. Then, the cutting roller rotated by the drive motor cuts the absorbent sheet in a predetermined shape, manufacturing the absorbent body.
In recent years, there is an increasing demand for mass production of absorbent articles, and accordingly, high-speed conveyance of absorbent sheet is required in manufacturing processes of the absorbent bodies.
However, if high-speed conveyance of the absorbent sheet is performed using the above-mentioned manufacturing apparatus, the slitting blades are not sufficiently pressed against the absorbent sheet conveyed at high speed to penetrate the absorbent sheet, leading to cases in which slits cannot be fully formed.
Moreover, parts of the absorbent sheet in which the slitting blades do not penetrate are increased in density, having greatly increased hardness. As a consequence, the absorbent article using this absorbent body may have increased stiffness, leading to possible degradation in flexibility.